Alphys's Amalgmates
by Omoni
Summary: A look at an alluded-to possible fate for both Alphys and Undyne, taking place during and following Chara's (aka Kill All Monsters) Playthrough. It contains ALL THE SPOILERS, FOR ALL THREE TIMELINES, so finish the game before reading this!


_Writer's Note: Okay, so this is weird, even for me, so please keep that in mind as you read. This idea was one that wouldn't get out of my head, one that tormented me for no other reason than to torment me, so in hopes of silencing it, here it is. This is from UNDERTALE (obviously), but what isn't obvious at first is which timeline it is, so I'll tell you: this is Chara's. This is what came to my head when wondering about Alphys's fate - as well as the fate alluded to for Undyne. So in case you missed it, THIS FIC TAKES PLACE DURING CHARA'S (aka "Kill All Monsters") TIMELINE and contains ALL THE SPOILERS EVER. DON'T READ THIS UNLESS YOU'VE PLAYED THIS TIMELINE. It also spoils pretty much all of the lore, even the Pacifist (Frisks's) timeline. Also, again, this is a first foray, so if I mess up, forgive me. Here we go._

 **Alphys's Amalgamates**

The amalgamates were restless today. Alphys watched them nervously, watching each of them examine - then accept - their meals in a somewhat squishy manner. Distantly, somewhere in the depths of the fake lab, her cellphone rang, its tinny ring tone insistent and sharp. Despite how many times she tried to hide the thing, one of the amalgamates - one in particular - always seemed to find it and bring it back to her, usually more insistent than the thing's ring, and twice as grumpy.

It was likely why that one, at this moment, was not eating with the others. Alphys wiped the sweat from her forehead, then tried to clean her glasses with her already-sweaty lab coat. There was no use in denying that she still had some lingering fear whenever she saw them, but more often than not, that fear was easily replaced with real, growing affection. In her way, she adored them all - especially Dogamy, her second-favourite - and despite their constant mutating and shape-shifting (so often she no longer took notes; and who else would read them but herself, anyway?), they all had their own quirks, remnants of memories long-gone with what they had once been. She wondered if their families still missed them. She wondered if those families were still safe...

The trilling stopped, for the moment, and Alphys closed her eyes in relief. She hadn't heard a word from anyone since she had buried herself deep in the bowels of her true lab with the amalgamates. Her final contact with the world had been a final text to Asgore, before she made one last stop to the surface forever (the text, if you wondered, was this: "SITUATION NOT GOOD; ABSORB THE SIX SOULS NOW! And good luck. A."). As far as she knew, the human was still out there, still bent on dust-shed, who was now being called a name that hadn't been spoken in a long time, one that still held the power to render a monster speechless or in tears. Alphys knew; she had been one of them, had shed many tears, especially when... _especially when..._

The ringing started up again, sending Alphys's already taxed heart racing once more. She turned to the doorway, realising that the sound was now getting closer. Instead of trying to run away - that never worked on this amalgamate, anyway - Alphys decided to wait, instinct telling her it was the only thing to do. She watched the others eat, her mind drifting in and out of memory.

* * *

They had all watched it from the flickering, grainy image that the hidden camera sent back to Alphys's cramped fake-office, in the front row of a crowd of monsters packed toe-to-toe in that small space, each desperate to see the outcome. As it had not been in her true office, Alphys remained protected from being forced to reveal her secrets, for now, but that didn't stop the horror from consuming her heart all the same.

She had promised Undyne she would watch the fight to the very end, no matter the outcome, to ensure that, no matter which outcome it resulted in, Alphys would be ready with the next step they had planned together – evacuation. (She _knew_ she had done everything she could to safeguard the remaining monsters, now. She had planned once they realised who the human actually was, while she was fine, so of course the plans had been, too.)

And Alphys always kept her promises. Even if keeping them meant breaking her own heart.

* * *

Silence again. Alphys waited, then relaxed a little then it started up again. She watched the door like she had watched that screen.

* * *

Undyne had never wanted to be a test subject. She usually, when asked, snorted the offer away, citing, "If I can't stop someone as I am now, I deserve to die!" And she flashed that toothy grin to emphasize this.

But that had been before.

When the news came to her that not only were the ruins completely sealed off, but their guardian - Toriel, their queen - was now dust, Undyne had rushed to Alphys's lab in a panic, almost to the point of getting completely dried out as a result; Hotland had never been kind to her. Before she even allowed herself a drink, she was already speaking.

"Toriel... Queen Toriel..." Undyne had barely remembered to remove her helmet before she spoke, holding it limply in one hand, a mug of water in the other. This sent Alphys into a sweat-drenched panic of her own, and would not allow Undyne to speak until she drained the mug. She did so, dropped it, and grabbed Alphys by the shoulders, her metal gloves feeling both hot and cold against her, even through the thick fabric of her lab coat. "She's dead." And here, just once, Undyne's lips trembled, ever so slightly. "The human... they're on their way to Snowdin. Before they get there, I need... I need you to..."

Their eyes met, and suddenly Alphys felt like Undyne had just accidentally thrown her too hard into something. Somehow, she knew exactly what Undyne was going to say, before she had even drawn the breath to say it. While not knowing the entire extent of it, Undyne had been let in on some of what Alphys had experimented with – and on. As Royal Guard (and mostly because she was extremely nosy and pestered both Asgore and Alphys until they relented), she had the right to know what she might have to protect against, later.

"Explain it to me, Alphy," she had said, her voice a desperate command. "All of it, this time. Then shoot me up and let me go."

 _Let you go, indeed,_ was her first thought. She lowered her head, her glasses fogging with her panicked breathing. But slowly, she nodded.

* * *

"Ow," Undyne scrunched her face up, as soon as Alphys had carefully stuck a syringe full of bright red liquid into the skin beneath the scales of her arm. As a result, Undyne exaggerated her whines at first, even before the needle made contact with her skin, which made Alphys smile despite herself. Even as the hurt was cleaned and bandaged, still Undyne milked it for what it was worth. At first.

Until suddenly, Undyne sat up straight, her eye wide and her mouth open in surprise. She then shuddered, closing her eye and hunching forward, which of course had Alphys at her side at once, checking her over in a panic, speaking nothing but stuttered syllables, until a hand was placed gently atop her spiky head, halting her.

"I'm okay," Undyne said, opening her eye slowly, her fingers twitching a little on Alphys's scalp. "It feels... weird. Like I'm so angry..." she gritted her teeth as she said it. "But also incredibly powerful... motivated... like I can do _anything.._." Her eye shone bright, and she grinned wildly, looking absolutely thrilled. "I think this means it'll work!"

Alphys knew that, too. There was something undeniably feral about the way Undyne looked now, as she flexed and stretched each muscle and scale carefully, each adjustment increasing her grin.

 _Undyne is a Boss Monster,_ Alphys had thought. _Therefore, she has the strength to survive past becoming dust. If anyone can stop the human, now, it's her._

But then...

* * *

The door had almost caved into itself from the force of those - could they still be called knocks? - knocks upon it. Alphys hurriedly opened them, and in a manner of seconds, Undyne was there, right there in her arms, shaking from head-to-foot, still wearing her full armour.

Which was dusty.

"Papyrus..." Undyne croaked out, her voice low and hollow coming from behind her mask.

For a moment, Alphys felt what could only be called the precursors to an obvious fainting spell - there was no other term for it. Though her arms automatically went around Undyne, felt Undyne's head resting upon her shoulder, all she could see was white, and all she could hear was rushing blood.

Papyrus was - had been - Undyne's partner-in-arms and bestest friend for as long as anyone could remember either of them. If Papyrus was seen alone, he would eventually and quickly either be joined by his brother, sans, or by Undyne. Undyne loved Papyrus, loved how arrogantly soft he was, loved how he always tried to make people happy no matter what...

Those kinds of traits worked only on those with a similar disposition and mindset. It was clear that the human lacked both, and drastically.

"Does sans k-know yet?" Alphys suddenly wondered, her eyes still blind and her ears deaf, though at some point her hands had deftly unfastened Undyne's helmet and thrown it aside somewhere.

"I can't find him," Undyne murmured weakly. A tone Alphys had never heard before. She held Alphys tight, so tight that if she squeezed harder, Alphys would have no breath. Not that Alphys cared much if she did; she had dreamt of a moment like this, one she had seen so many times in her favourite anime. She was holding Undyne to her, actually holding her, one hand even reaching up to stroke the long, slightly-slimy, salty-smelling hair, supporting her, keeping her on her feet...

But not like this. The price was not worth the reward.

"Alphy."

She looked at Undyne, who was already staring back at her, that one eye as hard as glass. _And... was it...?_ Alphys blinked, thinking that, just for a moment, it looked as if the socket beneath Undyne's eyepatch seemed to... light up, too?

Undyne raised her head, and Alphys quickly let go as she usually did, never one to overstay a hug, never once presuming - correctly - that Undyne wanted her hands to stay. To make this point, Undyne scowled and tightened her own hold on Alphys, and the poor scientist nearly did lose all breath and faint, before being able to hug back once more.

This seemed to satisfy Undyne, which sent Alphys's mind into crazy romantic overdrive for a moment, before Undyne's gaze brought her back down to her feet. "I have to stop this human, Alphy."

Her gut went cold, and she jerked away, unable to help it. "N-no! You s-said th-that..." she was stammering now, emotions running too high to control. "That we ne-needed to ev-evacuate everyone from Sn-Snowdin to Hotland! Where... we... _all_ of us... would be safe."

Undyne slapped a hand to her breast angrily, stomping a foot on the ground to match. "And you can't do that while that human murders everyone!"

Alphys heard the crack in Undyne's voice and flinched away from it. "B-but Undyne... w-we... we n-need you, here..."

Undyne's face fell, the frustration easily shifting into something else - pain, and fury. "No, Alphy. The monsters need me to fight out there. I'm the Captain of the Royal Guard. The Queen..." She looked down, her lips twitching. "I've already failed the Queen." She gritted her teeth, her fists clenched. "Now, I need to make sure _not_ to fail for... everyone else."

Unspoken was the name that they both already knew they had failed, whom they were still mourning for.

"C-come one, Undyne," Alphys stammered, wringing her hands before her. "Y-you won't f-fail anyone. So, f-forget about fighting... we need you h-here..."

Undyne's face hardened yet again. "But if I fail, there will be no one left to need anyone, Alphy!"

 _Stop calling me that,_ Alphys had silently pleaded. _Stop calling me that, in a way that breaks both of our hearts..._

Before she could stop herself, Alphys muttered softly, "I...I n-need you."

* * *

Alphys jumped suddenly. Dogamy had slithered up to her, vibrating intensely and splattering ecto-drool all over her hands and feet. Dogamy didn't seem to like the newest amalgamate too much, mostly because when it appeared, Alphys had no eyes - or pets - for anyone else. Clearly, Dogamy also knew who was on its way from the sound of the phone, and was trying to distract Alphys away from it with its vibrations and ecto-drool placement.

"It's... okay," Alphys assured it gently, mind already back in time.

* * *

They had seen everything. All of the surviving monsters that had fled to Hotland had found a way to shuffle themselves all into the single, cramped room of the fake lab, staring as one at the flickering image of the human and Undyne facing each other. The human had just turned to attack a monster - one of the children whom had gone missing prior to evacuating - without any hesitation, weapon already out. In horror, the last monsters stood watching as the human almost murdered the child in cold blood. Undyne had caught up to the human and had seen the whole thing - and thus she had stepped in to take the blow.

Alphys felt as if she had been the one struck by that pitiless knife. She staggered as she watched Undyne stagger, almost falling to her knees. Indeed, she would have, and likely would not have gotten up, if her fellow monsters weren't already there to support her from all sides.

* * *

"I n-need y-you, t-too..."

Again, like the best of dreams, Alphys found herself engulfed in Undyne's armour-clad body. This time, it was Alphys who was held up, Alphys who was supported as she wept, as she was comforted...

She didn't know when she had started crying, but she couldn't stop. Undyne held her close, so close it hurt, but she embraced that feeling - embraced Undyne even more - and suddenly was wracked with body-shaking, air-stealing sobs.

"D-don't g-go, Undyne," Alphys pleaded into Undyne's shoulder. "Don't! We need you more, Undyne! _I_ need you more!"

* * *

It was the coldest reaction to a death that Alphys had ever seen. The human watched calmly as Undyne, struck down by that killing blow, tried to hold on, tried to laugh it all off, all as she struggled to keep her body in one piece.

It wasn't working.

Alphys heard someone... wailing, in the distance, and as she watched Undyne flicker in and out, Alphys heard that sound and wondered who else seemed to love Undyne as much as she.

But, wait... her throat hurt.

* * *

Alphys closed her eyes tight at that memory, flicking several drops of drool from her soaked fingers. She had lost most of her voice in that instant, screaming out over and over until, as if by magic, Undyne suddenly seemed to re-form and become solid once more.

Then, and only then, did Alphys allow herself a small flicker of hope.

 _What a fool,_ she thought of herself, now.

* * *

"Alphy..."

"U-undyne? A-are you going t-to s-stay?"

Gently, Alphys felt herself being pushed away from Undyne, held apart by Undyne's hands at her shoulders. Reflexively, Alphys reached out and tried to close the distance between them again, but to not avail - her arms weren't long enough, it seemed.

"Alphy..." Undyne's face crumpled, and she looked tired all of a sudden, very tired and almost ancient. "I..."

Alphys stared at her, before shaking her head. "No. _No._ "

"Alphy, I have to..."

"No!" She shut her eyes tight, wishing that this meant she no longer had to worry about the problem, so long as she didn't see it. It had always seemed to work for her, before.

"Alphy, come on..."

 _"NO!"_

* * *

Standing where Undyne once stood was still Undyne - only not. Before their eyes the monsters watched as their true hero, a being who was now laughing at the human-shaped chaos before her, laughing in vow to change that chaos into her own brand of order. The strength that poured forth, shifting Undyne into something bent on surviving, something beautiful and insane and very, very frightening.

And, for the moment, with each slice of a spear, the utterance of each cackle, finally gaining the upper hand.

* * *

"Determination."

Alphys stared at her, and Undyne nodded, her hold on the scientist's shoulders getting tighter. "You called it determination, right? What humans have, that can bring them back to life? That's what you gave me, right?"

Alphys's entire blood supply seemed to burst into flames hotter than that of the Core, its fire slowly evaporating her blood as she stood there.

Mechanically, she said, "Yes. Determination. That's what it's called."

"So why the hell are you afraid, you dork?" Undyne grinned, but her eye looked bright with unshed tears. "I'm not gonna let some punk-ass kid kill me!"

 _No, not directly. But by stepping in to save someone weaker than you... to protect those you love..._

That _could kill you._

* * *

The demi-goddess before them was like seeing Undyne in her true form, the way everyone else already saw her as: untouchable, unbeatable, and unstoppable.

Unless the opponent was just as determined.

It looked incredibly close, many, many times. Almost as if, somehow, the human managed to manipulate both itself and Undyne, keeping parts of their battle going on and on, the human seeming close and closer to death, before...

* * *

The sound of the ringtone was growing louder, still. Alphys sighed, watching as Dogamy seemed to snort at her before shuffling away, the others close behind it. That was fine. Patiently, Alphys stood straighter, her eyes on the door, waiting for the amalgamate to come to her. She always would wait, no matter what.

* * *

Undyne held Alphys close when she saw the scientist's expression. Alphys clung to her as best she could, trying to find some absurd way to either glue the Guard permanently to her, or to fold her up and hide her some place until it was safe, like a dimensional box. Humans always seemed to have dimensional pockets; why couldn't _everything_ work that way? Why couldn't Undyne hide in a dimensional box until the human was killed or had left the underground for good?

"Alphy...it's gonna be okay."

"D-don't go."

"I'll be okay!"

"Don't d-do it!"

"Alphy-"

" _No!"_ Alphys was sobbing again, her glasses fogging up. A monster's tears were far messier than a human's, she knew: in anime, humans cried tears like spun glass or ceiling crystals. But monsters like Alphys cried with their whole body.

"Alphy."

She listened, stitching every word Undyne spoke to her very soul, her fingers growing numb and cold as she held Undyne to her. Her whole body shook with her tears and yes, her rage, feeling helpless and stupid and scared, so incredibly scared...

"Alphy. Don't worry. I'll come back. I'll be determined, too. And I will always stay at your side, always. Try to stop me!"

* * *

That last hit was the worst one, the one that again brought Undyne to her knees, seeming to cut down the demi-goddess in one swing of an arm.

And that's when Alphys lost her voice completely; her screams drowned everything else, even the mayhem that now panicked the other monsters. Because only Alphys understood what she had truly done.

* * *

 _"I'll always come back, Alphy. I always cling hardest to those I love, you dummy. And Alphy..."_

* * *

Slowly, the last amalgamate made its way before Alphys, clutching the briefly silent cellphone to itself with long, metallic fingers. Occasionally, the fingers would lose their shape and the cell phone almost dropped several times, before solidifying its grip once more, the ghost of a proud smile flickered in and out of view.

* * *

" _Alphy... I love YOU most of all..."_

* * *

Looking back, she didn't remember too much following her last scream very clearly, the sound the embodiment of someone who has fought with everything they had for everyone they loved - only to lose it in one careless, casual flick of a child-sized knife. After she realised she had lost her voice and almost her mind, she did what every scientist does when faced with something that must be seen through to the end, no matter how painful or impossible it now seemed. With one of her alarm apps, she settled the crowd down, switched her phone to text-to-voice, and hurriedly went through with the plans.

Like she had promised.

She remembered the blurs of faces she knew and loved, looking to her, of all people, for guidance and protection, as if she were their hero now (a fantasy she would have dreamt never possible before was now a bitter pill she was forced to swallow dry, one of many), though of course she was anything but.

She remembered losing her temper at a couple of the younger monsters, the two who enjoyed selling garbage and had always teased her when they saw her but would weirdly later defend her if anyone else did the same. When they both insisted they "like, needed to use up these pretty pens, and tell the human what a puke they are!" Which, while she agreed with the sentiment, was hardly the time, and she forced them to finish the letter as they packed and leave it no matter what the state once they were done.

She remembered getting the notice about Metaton, that even despite everything she had tried to do for him, he still had fallen, at no thanks to her. She had slammed a fist into the monitor showing the news, and hadn't realised the damage done until she felt glass bite into her tough skin, not a small feat.

She remembered seeing Dogamy, first. Her eyes fell on its excitedly vibrating form, and suddenly, she tried to scream again, the sound that came out somehow more painful than any scream ever could be. And how Dogamy had come close to her and tried to pet her, which only made her cry harder.

She remembered the nightmares: almost reaching Undyne in time with another dose of determination, that alone being enough to save her, or being forced to watch Undyne die over and over as the human laughed at her, or the worst - seeing Undyne melt over and over again, forever, before vanishing into dust.

She also remembered harsh reality. The last image that the camera picked up had burnt itself into Aphys's mind so searingly it was like she could see it behind closed eyes: the human flicking their wrist back as Undyne's dust seemed to vanish, when in actuality it was already starting to pool together. Luckily the human had no eyes for this; they simply looked until they found the camera. When found, the human looked into it, grinning a wide and unrestrained smile, waving a hand caked with ashes, before laughing once and cutting the feed.

She wished she could scream again, scream and never stop, scream herself to death, even. But she didn't: first because her fellow monsters wouldn't let her, but then, on her own. They still needed her, it seemed, or at least, for now, one did.

When she finally woke up from that strange fugue, it was in the fake lab's upper floor, lying upon her now-unfolded bed, and she wasn't alone. Both of these things weren't expected, since she had cut all ties once closing the doors behind her. Her last memory prior was the tail-end of a bad panic-attack, one she, it seemed, had blacked-out from. This wasn't unusual, as her nerves had never been strong, even before all of this. But that had been in the true lab, and alone; the opposite of what was now. Which meant only one last monster.

Slowly, she turned and met the guest's gaze with her own.

It was sans.

By now, sans knew everything. He knew that Toriel had tried to save the human - and had died as a result. He knew how Papyrus had died, how the human had been successful in killing nearly every single monster left in their path - even a few of the temmies. He also knew everything about Alphys - and thus she knew there was no point in even trying to pretend ignorance of Undyne's fate.

They had always gotten along somehow, especially underline. She liked to use some of his clever puns in the Junior Jumble, and since he always complained about how easy they both were, she made sure he had last say every time she sent out a word search or a crossword. They both shared a similar love for someone larger than life, someone seemingly out of reach but always reaching back down to you. So while not normal, seeing sans wasn't too bad, though she was terrified of the reason.

He stared at Alphys, his skeletal grin strained and tired. He looked like she felt, really, until...

Suddenly, sans wasn't sans at all anymore. Alphys choked on another scream, the sight of sans's empty eye-sockets terrifying her to her core, though she didn't exactly know why. Something about that eyeless gaze seemed far more frightening than even the human's face: the human always wore a sneer, grinning when any monster showed them pain. This was not how sans looked at all. He looked at her and she saw pure agony in those empty pits, decades and decades worth of it, some caused by others, some caused by himself, even, but all of it was there, all at once, and Alphys could not look away.

"Determination," sans said now, his voice deeper than usual, colder, as if made of ice colder than Snowdin. "Undyne was injected with determination."

Alphys opened her mouth to speak, but there was no use, her voice was toast, even when she tried to soothe it with water. So instead, she nodded slowly.

"So, then, you know what's happened to her?"

She repeated the gesture, her eyes filling with hot, shameful tears.

Suddenly, his skeletal hand gripped hers, and his eyes were his own once more. She found herself calming, just a bit.

"find her," he said, his voice normal now, too; "and make sure she isn't found by anyone else."

Alphys nodded a third time.

sans squeezed her hand, then pushed himself to his feet. "welp, i've got a job to do." Though the words were casual, the voice was anything but; it seemed to echo, almost felt rather than heard. For a moment, Alphys had the strange urge to lecture him a fourth time on his constant misuse of the non-word 'welp' ("It's not a real word and never will be! Stop submitting it, please!"). Instead, Alphys lunged out and grabbed his hand back, stopping him. She met his empty gaze, this time without fear, wishing she could speak, but to no avail.

 _Kill the human,_ she wanted to plea, though her voice was still gone. _Kill them, and make sure they know why. And don't hold back._

His eyes seemed to drill into hers. Then they blinked slowly, his smile widening. "That human will be dust by the time I'm done," sans said, his voice once more an echo to be felt. "And you and I will dance upon its grave."

She nodded fiercely, then let his hand go, and with that he seemed himself again. "that dirty brother-killer is mine," he concluded, before walking casually to the "up" escalator. He tilted his head, then walked on it. Instead of being thrown back, sans merely walked down those steps as if they were immobile. He soon vanished from her sight.

She realised later she had forgotten to ask about Asgore.

* * *

 _"Alphy, I love you most of all."_

* * *

So one last time, Alphys left her next and went back towards Waterfall, a place burnt to memory. It hadn't taken long for her to find what now remained of Undyne. Indeed, it seemed to already be on its way to her lab - the real one - when Alphys found it.

"U-Undying," she called gently, waving it over to her side. "Let's go home n-now, o-okay?"

* * *

The cellphone - now deposited on the nearest desktop - began to ring again. A glance at it told Alphys it was a number she vaguely knew but didn't really care about. Instead, she ignored it, kneeling to Undying and carefully putting her arms around its constantly shifting, gelatinous body. In response, Undying seemed to slide closer, its limbs going around Alphys and clinging to her like fresh seaweed. It made a gentle sound, apparently having noticed Alphys's tears.

* * *

 _"I love you most of all."_

* * *

"I love you most of all, too," Alphys whispered, barely able to form the words properly. But that didn't matter to Undying. It made another sound - a trill of a long-lost chuckle, an exclamation of protest or shyness - and seemed to be pleased at last, able to ignore the phone along with Alphys as a result.

They remained like this for a long time. The phone rang a few times more before suddenly becoming silent, the eerie, wrong kind of silence. With dread, Alphys now realised why she was being called.

Distantly, she heard the sound of a muffled explosion coming from her fake lab. She shut her eyes tight, just like she had before, holding Undying to her without loosening her hold.

When she felt the walls shake and the floor beneath her buckle, still she did not move, keeping Undying to her. Even when she heard the cries from the other amalgamates, still she did not move.

Though she did cry. A great deal.

And finally, when those horrible sounds finally reached her room, she ignored the human's words, its gestures, even its face. Instead, she surrendered to the world behind her eyelids, a world in which humans are good and complicated and always try to help others, a world that never existed and, now, never would.

And when her body seemed to start to decay before her eyes, as she felt a distant but consuming pain fill her, still she did not let go. She did not open her eyes. Instead, she buried her tear-stained face into that ever shifting, familiar-yet-alien shoulder, and let it all go.

She whispered, "I w-will _always_ love you b-best, Undying... my Undyne... try t-to stop me."

And then, she was dust.


End file.
